Goodwill and Other Intangible Assets (Goodwill) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 28, 2019	Dec. 28, 2019	Dec. 29, 2018
Goodwill [Roll Forward]
Goodwill, gross beginning balance		$ 315,307,000	$ 311,856,000
Accumulated impairment losses, beginning balance		(44,519,000)	(32,351,000)
Goodwill, net beginning balance		270,788,000	279,505,000
Goodwill acquired during the year			3,463,000
Impairment losses	$ 0		(12,168,000)
Foreign currency translation adjustment		32,000	(12,000)
Goodwill, gross ending balance	315,339,000	315,339,000	315,307,000
Accumulated impairment losses, ending balance	(44,519,000)	(44,519,000)	(44,519,000)
Goodwill, net ending balance	270,820,000	270,820,000	270,788,000
Office Furniture
Goodwill [Roll Forward]
Goodwill, gross beginning balance		128,645,000	128,657,000
Accumulated impairment losses, beginning balance		(44,376,000)	(32,208,000)
Goodwill, net beginning balance		84,269,000	96,449,000
Goodwill acquired during the year			0
Impairment losses			(12,168,000)
Foreign currency translation adjustment		32,000	(12,000)
Goodwill, gross ending balance	128,677,000	128,677,000	128,645,000
Accumulated impairment losses, ending balance	(44,376,000)	(44,376,000)	(44,376,000)
Goodwill, net ending balance	84,301,000	84,301,000	84,269,000
Hearth Products
Goodwill [Roll Forward]
Goodwill, gross beginning balance		186,662,000	183,199,000
Accumulated impairment losses, beginning balance		(143,000)	(143,000)
Goodwill, net beginning balance		186,519,000	183,056,000
Goodwill acquired during the year			3,463,000
Impairment losses			0
Foreign currency translation adjustment		0	0
Goodwill, gross ending balance	186,662,000	186,662,000	186,662,000
Accumulated impairment losses, ending balance	(143,000)	(143,000)	(143,000)
Goodwill, net ending balance	$ 186,519,000	$ 186,519,000	$ 186,519,000